Centrifugal ring-grinding mill



21, 936., J. J. MOISAN 290387233 CENTRIFUGAL RING-GRINDING MILL FiledMarch 15, 1933 5 Sheds-Sheet 2 IN VEN TOR.

JEII-IH J- PlDISHbL Aprifi 21, 1936 J. J. MOISAN CENTRIFUGALRINGGRINDING MILL Filed March 15, 1953 3 Sheets-Sheet 3 INVENTOR. P III-JEIHN JJHEIISHN- W'fjy gm' PlEr'E Patented Apr. 21, 1936 STTES PATENTOFFIQE one-fourth to George M. Icard,

Calif.

San Francisco,

Application March 13, 1933, Serial No. 660,530

4 Claims.

The present invention relates generally to improvements in centrifugalring-grinding mills, and especially to mills adapted to both wet and drycrushing of ore, rock, or any crushable material that is to be reducedto any predetermined degree of fineness.

It is the primary object of the present invention to provide anefficient, non-clogging, and high velocity mill that has greater reducedwearing surface areas than the mills now in general use.

Anotherobject of the invention is toprovide a centrifugal ring-grindingmill of the class described, that is sufficiently light in constructionand adapted to carryeither the wet or dry' crushing process; andenabling the users of said mill to operate the same with greatly reducedmotive power.

A further object of the invention is the provision of a mill includingself-cleaning screening grids mounted in such a manner as to permittheir ready and uniform adjustment for the increasing or decreasing ofthe width of the passages between said grids at the will of the operatorof said mill. A further object of the invention is the provision of acentrifugal ring-grinding mill of the class described, which embodies aclassifier adapted to sort the material that has been crushed by saidmill, said classifier being equipped with grids of a similar nature tothose used in said mill and operated and controlled in a slightlymodified manner.

A further object of the invention is the provision of a mill of theclass described, which embodies means for returning oversize materialfrom the classifier to the mill for regrinding, or for removal of saidmaterial from the classifier at a point adjacent tothe top of said mill.

A still further object of the invention is to provide a mill of theclass described, which embodies means for normally causing the crushablematerial to be forced through the mill without employing any additionalscrew conveyor, hydraulic force, or blower.

A further important object of the invention is to provide a mill whichis so constructed that a number of nests or groups of annuli may be usedin proportion to the hardness of the material to be crushed.

A still further important object of the invention is to provide a millwhich is so constructed as to permit its being shipped in small sectionsto remote locations without weakening or loss of any of the millssalient features, also to provide for the ready inspection andreplacement of the ,in-

ternal parts subject to wear or operating damage.

In the accompanying drawings:-

Figure 1 is a longitudinal sectional elevationof the mill illustratingthe shell and lining thereof, the feed and discharge hoppers, framespacers, .51 frame spacer rings, a plurality of annuli, internal lockingrings for adjusting the screeninggrids, rubber shock and guide rings,also the classifier, adjustable scoop, return launder mechanism, sealeddust and splash housing, and standard for 1o holding said housing, alsomeans for mounting and driving said mill;

Figure 2 is a transverse section taken on the line 2-2 of Figure 1, andillustrating the location of the grinding annuli, mullers, screeninggrids, 1L5. shell lining, and internal rings .for adjusting thescreening grids;

Figure 3 is an enlarged sectional detail taken on the line 3-3 of Figure2, and illustrating the method used in mounting the screening grids, and20 the means for adjusting the size of the passages between thetriangular bars;

Figure 4 is a vertical sectional detail taken on the line 4-4 -.ofFigure 3 depicting means for retaining and removing the triangular bars;25

Figure 5 is a top plan view of the removable segments forming bearingcaps for the triangular bars;

Figure 6 is a reduced plan view of the castellated internal lockingrings to permit the insertion of 0 the bar-spacer and looking membersshown in Figures 3 and 4;

Figure '7 is a transverse section of the castellated internal lockingrings, whose flanges contact on their inner faces the frame spacer ringsof the mill;

Figure 8 is a transverse section of the classifier taken on the line 8-8of Figure 1, illustrating the screening grid, locking ring, adjustablescoop, return launder, stay bolts and pipe spacers, also showing thefine ground material passing through the passages between the triangularbars to the discharge hopper, and the coarser material being lifted upby centrifugal force to the adjustable scoop and return launder;

Figure 9 is a greatly enlarged fragmentary section of Figure 8,depicting in greater detail the method employed in mounting the lockingring, triangular bars, stay bolts and pipe spac- 50 ers, and bearingcaps for the triangular bars;

Figure 10 is a vertical section taken on the line lli-l0 of Figure. 9,illustrating the means of retaining the triangular bars;

Figure 11 is a top plan view of atypical bearing cap as applied to thetriangular bars mounted in the classifier head of said mill; and

Figure 12 is an enlarged perspective view of a triangular bar, asapplied to my invention.

In the description of the preferred form of my invention, as disclosedin the drawings, the various mechanisms include broadly, a cylindricalshell l3; feed hopper l4; frame spacers I5; grinding annulus nests I6;screening grids l1; classifier I 8; adjustable scoop and return laundermechanism I9; mill support rollers 20'; and motive power attachment 2|.

The mill comprises, specifically, the cylindrical shell l3 consisting ofa metallic cylinder 22 upon whose opposite ends are mounted the flangedmembers 23 and 24, and the mill tires 25 and 26, all clearly shown inFigure 1.

The cylindrical shell I3 is provided with a plurality of ringlikelinings 21 which are provided with various segments 28, 29, 38, 3|, 32,and 33, to facilitate their installation, as shown in Figure 2, the endfaces 34 and 35 of said segments being tapered to permit positivegripping of the frame spacers l5, whose detail parts will be hereinaftermore fully described.

The feed hopper |4 consists of a truncated cone shaped exterior shell 36provided with a suitable opening 31 permitting the entry of the millcharge, said feed hopper l4 being fitted with a similarly formedmetallic liner 38 which may be replaced when it becomes worn. The feedhopper I4 is securely fastened by means of bolts 39 to the flangedsection 23 of the cylindrical shell l3, as disclosed in Figure 1.

The frame spacers |5 are composed of a plurality of plates 48, so shapedas to fit snugly against the countersunk outer rings 4| abutting thecylinder 22, said outer rings being provided with a plurality of capscrews 42 securely holding the outer rings 4| and plates 4|] in rigidalinement. The internal faces of said outer rings 4| are equipped withreplaceable wearing plates 43.

Radially arranged about the center of the mill and projecting fromplates 48 are a plurality of studs 45 containing inner spacer rings 46and the screening grids IT, as shown in Figures 2 and 3, said innerframe spacer rings 46 have their opposite faces deeply grooved andhaving cemented therein rubber shock and guide rings 41, as depicted inFigures 1, 2, 3, and 4.

In the grinding compartments 48, 49, 50, 5|, and 52, are mounted a groupof grinding annulus nests l6 consisting of a plurality of members 53,54, and 55, of varying diameters. Inserted in the innermost part of eachsaid nest is a muller 56. Each of said grinding nests I6 is free toshift about within its respective grinding compartment irrespective ofthe action being taken by any of the other nests due to the rotation ofthe mill. The inner and outer peripheries of the grinding annuli 53, 54,and 55, and the outer faces of the muller 56 function as the activegrinding and crushing agents of the device.

Mounted between the plates 40 are the screening grids l1, comprisingtriangularbars 51, and bar-spacer and locking members 58, said barspacerand locking members being slidably mounted on a plurality of cap screws59 passing through the slots 68 and secured to the inner frame spacerrings 46, as shown in Figures 3 and 4.

The triangular bars 51 are provided with dowels 6| and 62 which functionas pivots for said bars to permit their rotation, as shown in Figures 3and 12. The inner frame spacer rings 46 are recessed and form halfbearings 63 to provide for the insertion of the dowels 6|, Figures 3 and4, and bearing caps 64 are securely fastened with cap screws 65 to saidinner frame spacer rings 46. The bearing caps 64 are provided withbearing grooves 66,- said grooves functioning as the outer half of thebearing surfaces for the dowels 6i and the drilled holes 61, as depictedin Figure 5, functioning as the gripping medium for the cap screws 65.

The plates 43 of the frame spacers I5 are provided with a plurality ofdrilled holes 44 to receive the dowels 62 of the triangular bars 51 andwith said holes acting as bearings for said triangular bars 51, asdisclosed in Figure 2. g The bar-spacer and locking members 58 are soshaped that they contact the triangular bars 51 upon two faces, thuspreventing any movement from the desired position predetermined by theoperator of the device. Shifted or changed positions of the triangularbars 51 are indicated by dot-and-dash lines in Figure 3.

The castellated rings 68 function as the shifting and locking devicesfor the various groups of screening grids l1, and said rings arefabricated from flanged members with the castellations 69 therein,permitting insertion of the bar-spacer and locking members 58, asdisclosed in Figures 2, 3, 4, and 6. Drilled holes 10, 1|, and 12 areprovided in said castellated rings 68 for obtaining any desired settingof the screening grids, namely-fine, medium, and coarse. The movement ofthe screening grids in any given direction will either increase ordecrease the passages between the triangular bars 51, thus limiting thesize of the material that may be passed between the triangular bars 51of said screening grids. The flanged portions 13 of said castellatedrings 68 abut the opposite ends of the barspacer and locking members 58at the points indicated by the numerals 14 and 14. The inserted bolts15, Figure 2, are removed from the frame spacer rings 46 when it isdesired to shift the position of said castellated rings.

The classifier I8 is composed of inner and outer ring frames 16 and 11,stay bolts 18, and pipe thimbles 19, said pipe thimbles holding saidinner and outer ring frames in spaced relation without causing any unduepressure to be applied to the triangular bars 51'. The triangular bars51' perform a similar screening operation in both the classifier and inthe screening grids between the various grinding compartments, and aretherefore of identical construction. The inner ring frame 16 is rigidlyheld against the flanged members 24 and abuts the end of the cylindricalshell I3, and is held rigidly in place by means of cap screws 80.

The locking ring 8|, as disclosed in Figures 1, 8, 9, and 10 is providedwith annularly arranged slots 82, position adjusting perforations 83,84, and 85, and is of like arrangement to the drilled holes 10, 1|, and12 of the castellated ring 68; and also includes triangular bar grippingmeans similar in form to those provided in the bar-spacer and lockingmembers 58 of the screening grids 1. Bolts 84', Figures 8, 9, and 10,inserted in the locking ring 8| are removed when it is desired to shiftsaid ring to a different position in order to change the grade of theclassifiers output.

The annularly arranged slots 82 are provided to permit the readyadjustme t of t e locking ring 8| without disturbing the tension on thestay bolts "I8 and pipe thimbles 1.9,as clearly disclosed in Figures 8and 9.

The outer ring frame 11 is recessed to form half bearings 86 forreceiving the dowels BI of the triangular bars 51, Figures 9 and 10,and. the internal bearing caps 81 are securely fastened by thecountersunk screws 88 to said outer ring frame 11. The bearing caps 81are so shaped as to conform with the inner face 'of the outer ring framell, as disclosed in Figures 9 and 11, and are provided with a pluralityof bearing surfaces 89, forming the inner half of the bearings for thedowels GI. The countersunk holes depicted in Figure 11 are provided for,and function as the gripping medium for the countersunk screws 88. Theinner ring frame 16 is provided with a plurality of drilled holes I6 toreceive the dowels 62' of the triangular bars 51, and said holesfunctioning as bearings for said triangular bars 51, as disclosed inFigure 1.

The classifier I8 is equipped with a dust and. splash housing 90supported by the upright standard SI, and provided with an opening 92permitting the desired adjustment of the scoop and return laundermechanism I9. The dust and splash housing 90 is also provided with arubber sealing ring 93 contacting the mill tire 26, as depicted inFigure 1 of the drawings, and said ring prevents dust particles of therefined material from becoming entrapped upon the working surface of themill tire 20; thus eliminating the uneven rotation of the device. Adischarge hopper 94 of truncated cone shape is provided at a suitablepoint in the lower part of the dust and splash housing 90, and isequipped with an ejection port 95, Figures 1 and 8 of the drawings.

The adjustable scoop and return launder mechanism I9 comprises, atelescopic scoop lip 96, discharge body casting 91, and adjusting lockbolt and nuts 98, said lock bolt and nuts being securely fitted into thelugs in Figures 1 and 8. The discharge body casting 91 is rigidlymounted upon a slidable and rotatable axis I00, and said axis isprovided with inner and outer U-clamps IBI and I02, with said clampsfirmly gripping the upright standard 9|. When the U-clamps IOI and I02are loosened, the axis I00 may be shifted to any desired position asindicated by the double directional arrows shown in Figures 1 and 8. Thereturn launder fitting I03 whose transverse section is substantially ofU-shape, is mounted directly beneath the discharge body casting 91, andsaid return launder fitting I03 is rigidly mounted upon a slidable axisI04 securely fastened by means of inner and outer U-clamps I05 and I06,to the upright standard 9|. The return launder fitting I03 may be movedby the operator of the device in accordance to the position taken by themembers 53 and 54 of the grinding annuli in the grinding compartment 52.Should the operator of the device desire to remove entirely the materialcaught by the adjustable scoop and return launder mechanism l9, hedisconnects the return launder fitting I03 and substitutes a materialtransfer trough (not shown), thus disposing of said material in anydesired manner.

The mill support rollers 20 consist of suitable wheels I01, meshingfrictionally, with the mill tires 25 and 26, all clearly disclosed inFigure 1, said wheels I01 being press-fitted to shafting I08 andoperating through bearings I09, which bearings are mounted upon adequatefoundations I I0.

The mill, as disclosed in the drawings, is driven by the motive powerattachment 2| consisting of 99, all clearly shown.

a pulley I'=II securely fastened to the cylindrical shell I3 of themill. The rubber belt II2 transmits the necessary power to rotate themill from any convenient source not disclosed in the drawings.

Following a period of continuous operation the grind-members '53, 54 and55 become worn to such an extent that their operation is no longerefficient, said members should then be removed from the mill and if anytwo of the above mentioned members will telescope together, they may bewelded into a single unit and again used in the mill.

In recapitulationz- The. crushable material in being treated in themill, passes from the feed hopper I4 through a series of screening gridsI1 in the direction indicated by the arrows in Figures 1 and 3 and intothe first grinding compartment 48, where the action of the annulus nestI6 performs the first or coarsest grinding. The crushed material is nowpassed through the screening grids I'I into the next compartment 49where said material is again subjected to grinding. A like operation isperformed in each succeeding compartment until the now refined materialdrops into the classifier I8. The classifier I8 being securely fastenedto the body of the mill, is therefore constantly rotating and screensthe refined material as it is received from the final grin-dingcompartment 52. This rotation causes the fine particle-s of the refinedmaterial to pass between the triangular bars 5'! into the dischargehopper 94 and thence out through the port 95, as indicated bydirectional arrows in Figures 1 and 8. The remaining large material isnow elevated by centrifugal force and is caught by the adjustable scoopand return launder mechanism I9, as depicted in Figure 8, and is eitherreturned to the mill for more grinding or is with-drawn from theclassifier by means of a material transfer trough. Should the operatorof the mill desire to screen the material that has been refined to sucha degree of fineness that it is impossible to further reduce thepassages between the triangular bars 51' to the desired width, theoperator partly collapses the telescopic scoop lip 96. The addedclearance between the triangular bars 51' and the telescopic scoop lip955 permits the large material to continue around the mill, forming afilter bed through which only extremely fine material can be passed. Thereadjustment of the telescopic lip 96 to its original setting promptlyremoves this filter bed and the mill is free to operate as originallyintended.

Should it be desired to treat the; crushable material in a bone-drymanner, it has. been found that the triangular bars 51 and 51, beingmounted in substantially blower-vane positions, do create enough draftsuction when the device is rotated, to cause the material charge to bepulled rapidly through the mill, and thus greatly increasing theoperating efficiency of the device.

Having thus described my invention and with intent not to be limited toor by details of construction of the particular disclosure embodied inthe drawings or hereinbefore described.

I claim and desire to secure by Letters Patent of the United States thefollowing:-

1. In a centrifugal ring-grinding mill of the class described, incombination, a classifier associated therewith, said classifierembodying a plurality of angularly faced grids, means for rotatablymounting said grids, and ring means associated therewith for changingthe angular positions thereof to increase and decrease thepassagestherebetween.

2. In a centrifugal ring-grinding mill of the class described, includinga classifier embodying a plurality of screening grids, said gridsarranged in concentric relation to the axis of rotation of theclassifier, said grids being mounted for independent axial rotation, anda ring cooperating therewith, to retain the same in fixed positions, andalso including means for the adjustment of same relative to each other.

3. In a centrifugal ring-grinding mill of the class describedcomprising, cylindrical means for containing and rotating a body of oreto be pulverized, means for propelling the material thru said millconsisting of a plurality of radially arranged groups of triangularlyformed members,

ring means for adjusting said groups to limit the passage of oretherebetween whereby the ore is ground to a predetermined degree offineness.

4. In a device of the class described comprising a rotatable shelladapted to contain a body of material to be ground, a plurality ofgrinding compartments arranged therein, grinding annuli in saidcompartments, said grinding annuli consisting of a plurality of nestedrings arranged in the various compartments, and sorting and distributingmeans adapted to propel the material from compartment to compartmentcomprising, triangular elements arranged between each compartment, andmeans for adjusting said triangular elements.

JOHN J. MOISAN.

